1. Field of the Invention
The invention relates to refrigerated shipping containers, and more particularly to containers for cryogenic cooling.
2. Background Information
There are a number of situations in which a temperature controlled container is useful. One of these is when a manufacturing process utilizes a temperature dependent product. For instance, epoxy is formed from two chemicals that are mixed together. After the chemicals are mixed together there is a short amount of time available before the epoxy sets up into a hard material. In some operations, it is desirable to mix up a large quantity of epoxy, and delay the onset of hardening. This can be accomplished in a container in which the mixed epoxy can be placed, with cooling provided to delay the onset of hardening. With this kind of capability, one area of a plant can mix the epoxy, and it can be shipped in a cooled container to another area of the plant where it is utilized. Also, larger quantities of epoxy can be mixed together, and utilized by taking a desired quantity out of the cooled box. In this way, all of the epoxy used on a project would have the same mixture of the two components and thus, would be more uniform. There are other temperature dependent manufacturing steps which could utilize a temperature controlled box, especially one that could achieve extremely low temperatures at a reasonable cost, and which could operate without external power and could be transported easily.
Another situation in which a temperature controlled container would be useful is in medical use, field hospital use and emergency situation response. In such situations, what is needed is a container which is low-tech, can be built to the capacity required for any tasks, can economically keep materials at a low temperature for a long period of time, and which don't require an electrical connection. Such a container could be utilized in field hospitals in the military, for storing blood plasma, vaccines, and other supplies used in the hospital. It could also be utilized for transporting tissues, organs for transplant and other medical related items. In a disaster area, it could hold vaccines, medicines, blood plasma and other medical materials which need refrigeration or freezing.
Another area in which a temperature controlled container is needed, is in the transport of foods in a frozen or refrigerated state. Certain foods are in high demand in areas that are far from where the food is processed. For such foods, it is highly important that the food arrive at its destination in prime condition. This would be true for high valued foods such as fish products bound for the Japanese or other distant markets, Kobe beef being transported from Japan, caviar being shipped from Russia, and other specialized, high value items.
Another need is in the food service field. A temporary or portable freezer may be needed in a field kitchen, or in a restaurant with a need for a temporary freezer to replace a walk-in freezer that is being repaired or replaced, or if the need arose, to permanently serve as the facility freezer. This would be especially true in a remote location where power may not be available, but weekly shipments of dry ice are available.
The prior art for accomplishing these tasks include an insulated picnic box which typically has a hinged lid and a layer of insulation. The hinged lid is closed by a latch. For certain uses of such a picnic cooler, frozen food is placed inside the cooler, along with ice or dry ice, and the picnic cooler lid is closed and possibly taped shut. Use of such a pack will preserve food for several days, but often when the food is opened it is floating in water from the melted ice, or it is melted because it has thawed. Also, if the lid has to be opened and closed very often, heat is introduced to the food inside and its frozen time and temperature are reduced.
Another prior art system is to use a powered refrigeration system with a shipping container. This can be a motorized device that is powered by a fuel such as gasoline or diesel, and runs a compressor and a refrigeration unit in a conventional way. Such a refrigeration unit has disadvantages, which are that it produces exhaust fumes which can accumulate in a confined room, it needs to burn fuel as it operates and it cannot achieve a low enough temperature for certain applications.
Another prior art system uses liquid CO2 to freeze materials, which are then placed in an insulated container. This method results in a container that is able to maintain a temperature of −80° F., but is not self-contained and requires a separate freezing system.
What is needed is a low-tech container which has a very high insulation value, does not require an electrical connection, can keep product at a super low temperature, can keep foods either frozen or refrigerated or both at the same time in different compartments, for a long enough period of time to accomplish shipping, or to be useful in the field.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.